(a) Field of the Invention
The present invention relates to thin film transistor array panels and the manufacturing methods of the same.
(b) Description of the Related Art
A liquid crystal display (LCD) is one of the most popular flat panel display (FPD). The liquid crystal display has two panels having electrodes for generating electric fields and a liquid crystal layer interposed therebetween.
The transmittance of incident light is controlled by the intensity of the electric field applied to the liquid crystal layer.
In the most widely used liquid crystal display, the field-generating electrodes are provided at both of the panels, with one of the panels having switching elements such as thin film transistors, and the other panel having color filters.
In general, a thin film transistor array panel is manufactured by a photolithography process using five or six photomasks and a color filter panel is manufactured by a photolithography process using three or four photomasks.
Since the photolithography process costs expensive, the number of the photolithography steps needs to be minimized.
It is therefore an object of the present invention to provide methods for manufacturing thin film transistor array panels for liquid crystal displays with a reduced number of masks employed in the photolithography processes.
It is another object of the present invention to simplify methods for manufacturing thin film transistor array panels for liquid crystal displays.
These and other objects are provided, according to the present invention, by forming a portion of a photoresist layer (photoresist) that is thinner than another portion between a source electrode and a drain electrode before the two electrodes are formed. Thus, the thin portion protects underlayers when some layers are etched, and is also etched along with other layers to expose its underlayer. Also, red, green, and blue color filters are used as a passivation layer covering a thin film transistor and wires. A wire may be formed of a photosensitive conductive material. The color filters may be formed of photosensitive material and screen printed or offset printed. A light blocking layer made of the color filter may be formed on the channel of the thin film transistor.
In a manufacturing method according to the present invention, a gate wire including a gate line and a gate electrode connected to the gate line is formed on an insulating substrate. A gate insulating layer pattern covering the gate wire, a semiconductor pattern, and an ohmic contact layer pattern are formed. A data wire including a data line, a source electrode and a drain electrode is formed. The source electrode and the drain electrode are made of the same layer on the ohmic contact layer and separated from each other. The data line is connected to the source electrode. Then, red, green, and blue color filters covering the data wire is formed. The color filter has a first contact hole exposing the drain electrode. A pixel electrode is formed and connected to the drain electrode through the first contact hole. Here, the source electrode and the drain electrode are separated by a photolithography process using a photoresist pattern, and the photoresist pattern has a first portion having a first thickness that is at least located between the source electrode and the drain electrode, a second portion having a second thickness thicker than the first portion, and a third portion having a third thickness thinner than the first thickness.
It is preferable that a mask used for forming the photoresist pattern has a first, a second, and a third part, and that the transmittance of the third part is higher than the first and the second parts, the transmittance of the first part is higher than the second part, the photoresist pattern is made of positive photoresist, and the mask is aligned such that the first, the second, and the third parts respectively face the first, the second, and the third portions of the photoresist pattern in an exposing step.
The first part of the mask may include a partially transparent layer, or a pattern smaller than the resolution of the exposure used in the exposing step.